Prescriptions for hydrocodone combination products (HCPs) fell significantly after the US Drug Enforcement Agency (DEA) tightened restrictions on those drugs, according to a study published Monday in JAMA Internal Medicine.

For years the US has been in the grips of a prescription drug abuse epidemic, in part driven by the availability of hydrocodone and other opioids such as oxycodone, codeine and methadone. In 2013, more than 200 million prescriptions for opioids were filled in the US, 136 million of which were for hydrocodone.

The opioid epidemic is also seeing increased attention in Congress. Last week, Sen. Edward Mackey (D-MA) placed a hold on the vote to nominate Robert Califf as US Food and Drug Administration (FDA) Commissioner, and today, six senators wrote to the Centers of Disease Control and Prevention (CDC) urging the agency to release its long-delayed opioid prescribing guidelines.

Rescheduling HCPs

When the Controlled Substances Act was enacted in 1971, drugs containing hydrocodone as the only active ingredient were listed on Schedule II, signifying a high potential for abuse, while HCPs were placed on the less restrictive Schedule III. Notably, prescriptions for Schedule II drugs cannot by refilled, unlike those for Schedule III drugs, which can be refilled for up to six months.

DEA first requested the Department of Health and Human Services (HHS) provide it with a recommendation for rescheduling HCPs in 2004. In its response in 2008, HHS responded that HCPs should remain Schedule III drugs.

Under the 2012 Food and Drug Administration Safety and Innovation Act (FDASIA), the US Food and Drug Administration (FDA) was instructed to hold a public meeting to gather input to inform its recommendation to DEA on scheduling HCPs.

In 2013, FDA convened its Drug Safety and Risk Management Advisory Committee (DSaRM) to discuss whether HCPs should be rescheduled. After two days of deliberation, the panel recommended HCPs be rescheduled in a 19-10 vote.

Then, on October 6 2014, following a notice of proposed rulemaking, which drew 573 comments, DEA rescheduled HCPs from Schedule III to Schedule II.

Effect of Rescheduling

To determine the effect rescheduling had on the number of prescriptions for HCPs, officials from HHS and FDA compared the number of prescriptions filled in the 36 months prior to the rescheduling to the 12 months after.

Prescriptions for liquid and tablet forms of HCPs declined 8.4% and 6.0%, respectively, over the 36 months prior to rescheduling.

However, after moving to Schedule II, prescriptions for liquid and tablet forms of HCPs dropped by 22% and 16%, respectively. According to the authors, 73.7% was due to the elimination of refills on these drugs.

The researchers also saw a slight increase in other opioid combination products corresponding with DEA's action, though this was not enough to "substantially offset" the drop in HCP prescriptions.

JAMA Internal Medicine